Tumor microenvironment-activated single-atom platinum nanozyme with H2O2 self-supplement and O2-evolving for tumor-specific cascade catalysis chemodynamic and chemoradiotherapy

A Versatile Nanozyme-Based NADH Circulating Oxidation Reactor for Tumor Therapy through Triple Cellular Metabolism Disruption

Nanozyme-based metabolic regulation triggered by tumor-specific endogenous stimuli has emerged as a promising therapeutic strategy for tumors. The current efficacy, however, is constrained by the limited concentration of endogenous substrates and the metabolic plasticity of tumors. Consequently, the implementation of efficient metabolic regulation in tumor therapy is urgently needed. Herein, a versatile nanozyme-based nicotinamide adenine dinucleotide (NADH) circulating oxidation nanoreactor is reported. First, the synthesized cobalt-doped hollow carbon spheres (Co-HCS) possess NADH oxidase (NOX)-mimicking activity for the NADH oxidation to disrupt oxidative phosphorylation (OXPHOS) pathway of tumor cells. Second, the substrate-cycle manner of Co-HCS can be used for NADH circulating oxidation to overcome the limitation of substrate deficiency. Finally, 2-Deoxy-D-glucose (2-DG) and 6-aminonicotinamide (6-AN) are introduced to block glycolysis and pentose phosphate pathway (PPP), thus creating a versatile nanozyme-based NADH circulating oxidation nanoreactor (Co-HCS/D/A) for tumor therapy through triple cellular metabolism disruption. In vitro and in vivo results demonstrate that the designed nanoreactor not only enhances the catalytic efficiency but also disrupts the tumor metabolic homeostasis, leading to efficient therapy outcome. This study develops a novel NADH circulating oxidation nanoreactor for tumor therapy through triple cellular metabolism disruption, which addresses the limitations of current nanozyme-based metabolism regulation for tumor therapy.

Single-Atom-Based Nanoenzyme in Tissue Repair

Since the discovery of ferromagnetic nanoparticles Fe3O4 that exhibit enzyme-like activity in 2007, the research on nanoenzymes has made significant progress. With the in-depth study of various nanoenzymes and the rapid development of related nanotechnology, nanoenzymes have emerged as a promising alternative to natural enzymes. Within nanozymes, there is a category of metal-based single-atom nanozymes that has been rapidly developed due to low cast, convenient preparation, long storage, less immunogenicity, and especially higher efficiency. More importantly, single-atom nanozymes possess the capacity to scavenge reactive oxygen species through various mechanisms, which is beneficial in the tissue repair process. Herein, this paper systemically highlights the types of metal single-atom nanozymes, their catalytic mechanisms, and their recent applications in tissue repair. The existing challenges are identified and the prospects of future research on nanozymes composed of metallic nanomaterials are proposed. We hope this review will illuminate the potential of single-atom nanozymes in tissue repair, encouraging their sequential clinical translation.

Nanozymes with biomimetically designed properties for cancer treatment

Nanozymes, as a type of nanomaterials with enzymatic catalytic activity, have demonstrated tremendous potential in cancer treatment owing to their unique biomedical properties. However, the heterogeneity of tumors and the complex tumor microenvironment pose significant challenges to the in vivo catalytic efficacy of traditional nanozymes. Drawing inspiration from natural enzymes, scientists are now using biomimetic design to build nanozymes from the ground up. This approach aims to replicate the key characteristics of natural enzymes, including active structures, catalytic processes, and the ability to adapt to the tumor environment. This achieves selective optimization of nanozyme catalytic performance and therapeutic effects. This review takes a deep dive into the use of these biomimetically designed nanozymes in cancer treatment. It explores a range of biomimetic design strategies, from structural and process mimicry to advanced functional biomimicry. A significant focus is on tweaking the nanozyme structures to boost their catalytic performance, integrating them into complex enzyme networks similar to those in biological systems, and adjusting functions like altering tumor metabolism, reshaping the tumor environment, and enhancing drug delivery. The review also covers the applications of specially designed nanozymes in pan-cancer treatment, from catalytic therapy to improved traditional methods like chemotherapy, radiotherapy, and sonodynamic therapy, specifically analyzing the anti-tumor mechanisms of different therapeutic combination systems. Through rational design, these biomimetically designed nanozymes not only deepen the understanding of the regulatory mechanisms of nanozyme structure and performance but also adapt profoundly to tumor physiology, optimizing therapeutic effects and paving new pathways for innovative cancer treatment.

Bimetallic PtPd Atomic Clusters as Apoptosis/Ferroptosis Inducers for Antineoplastic Therapy through Heterogeneous Catalytic Processes

Active polymetallic atomic clusters can initiate heterogeneous catalytic reactions in the tumor microenvironment, and the products tend to cause manifold damage to cell metabolic functions. Herein, bimetallic PtPd atomic clusters (BAC) are constructed by the stripping of Pt and Pd nanoparticles on nitrogen-doped carbon and follow-up surface PEGylation, aiming at efficacious antineoplastic therapy through heterogeneous catalytic processes. After endocytosed by tumor cells, BAC with catalase-mimic activity can facilitate the decomposition of endogenous H2O2 into O2. The local oxygenation not only alleviates hypoxia to reduce the invasion ability of cancer cells but also enhances the yield of •O2- from O2 catalyzed by BAC. Meanwhile, BAC also exhibit peroxidase-mimic activity for •OH production from H2O2. The enrichment of reactive oxygen species (ROS), including the radicals of •OH and •O2-, causes significant oxidative cellular damage and triggers severe apoptosis. In another aspect, intrinsic glutathione (GSH) peroxidase-like activity of BAC can indirectly upregulate the level of lipid peroxides and promote ferroptosis. Such deleterious redox dyshomeostasis caused by ROS accumulation and GSH consumption also results in immunogenic cell death to stimulate antitumor immunity for metastasis suppression. Collectively, this paradigm is expected to inspire more facile designs of polymetallic atomic clusters in disease therapy.

Photothermal-promoted O2/OH generation of gold nanotetrapod @ platinum nano-islands for enhanced catalytic/photodynamic therapy

Ultrasmall platinum (Pt) nanozymes are used for catalytic therapy and oxygen (O2)-dependent photodynamic therapy (PDT) by harnessing the dual-enzyme activities of catalase (CAT) and peroxidase (POD). However, their applications as nanocatalysts are limited due to their low catalytic activity. Herein, we constructed a photothermal-promoted bimetallic nanoplatform (AuNTP@Pt-IR808) by depositing ultrasmall Pt nano-islands and modifying 1-(5-Carboxypentyl)-2-(2-(3-(2-(1-(5-carboxypentyl)-3,3-dimethylindolin-2-ylidene)ethylidene)-2-chlorocyclohex-1-en-1-yl)vinyl)-3,3-dimethyl-3H-indol-1-ium bromide (IR808) on gold nanotetrapod (AuNTP) with CAT/POD activities to enhance PDT/catalytic therapy. In the tumor microenvironment, the ultrasmall Pt can catalyze endogenous hydrogen peroxide (H2O2) to produce O2, relieving tumor hypoxia and enhancing the PDT performance. Moreover, AuNTP integration into the bimetallic nanoplatform showed good electron transfer properties and promoted the POD activity of ultrasmall Pt. Importantly, AuNTP@Pt-IR808 possessed higher photothermal conversion performance than single AuNTPs, which enhanced photothermal therapy (PTT). It also accelerated the CAT/POD dual-enzyme activities, and promoted the generation of singlet oxygen (1O2) and hydroxyl radical (OH). By enhancing the performances of PTT/PDT/catalytic therapy, the developed AuNTP@Pt-IR808 nanoplatform demonstrated good antitumor efficacy against breast cancer.

Multienzyme-Like Nanozymes: Regulation, Rational Design, and Application

Nanomaterials with more than one enzyme-like activity are termed multienzymic nanozymes, and they have received increasing attention in recent years and hold huge potential to be applied in diverse fields, especially for biosensing and therapeutics. Compared to single enzyme-like nanozymes, multienzymic nanozymes offer various unique advantages, including synergistic effects, cascaded reactions, and environmentally responsive selectivity. Nevertheless, along with these merits, the catalytic mechanism and rational design of multienzymic nanozymes are more complicated and elusive as compared to single-enzymic nanozymes. In this review, the multienzymic nanozymes classification scheme based on the numbers/types of activities, the internal and external factors regulating the multienzymatic activities, the rational design based on chemical, biomimetic, and computer-aided strategies, and recent progress in applications attributed to the advantages of multicatalytic activities are systematically discussed. Finally, current challenges and future perspectives regarding the development and application of multienzymatic nanozymes are suggested. This review aims to deepen the understanding and inspire the research in multienzymic nanozymes to a greater extent.

A pH-Sensitive Nanoparticle as Reactive Oxygen Species Amplifier to Regulate Tumor Microenvironment and Potentiate Tumor Radiotherapy

Background

Radiotherapy is a widely used clinical tool for tumor treatment but can cause systemic toxicity if excessive radiation is administered. Although numerous nanoparticles have been developed as radiosensitizers to reduce the required dose of X-ray irradiation, they often have limitations, such as passive reliance on radiation-induced apoptosis in tumors, and little consider the unique tumor microenvironment that contributes radiotherapy resistance.

Methods

In this study, we developed and characterized a novel self-assembled nanoparticle containing dysprosium ion and manganese ion (Dy/Mn-P). We systematically investigated the potential of Dy/Mn-P nanoparticles (NPs) as a reactive oxygen species (ROS) amplifier and radiosensitizer to enhance radiation therapy and modulate the tumor microenvironment at the cellular level. Additionally, we evaluated the effect of Dy/Mn-P on the stimulator of interferon genes (STING), an innate immune signaling pathway.

Results

Physicochemical analysis demonstrated the prepared Dy/Mn-P NPs exhibited excellent dispersibility and stability, and degraded rapidly at lower pH values. Furthermore, Dy/Mn-P was internalized by cells and exhibited selective toxicity towards tumor cells compared to normal cells. Our findings also revealed that Dy/Mn-P NPs improved the tumor microenvironment and significantly increased ROS generation under ionizing radiation, resulting in a ~70% increase in ROS levels compared to radiation therapy alone. This enhanced ROS generation inhibited ~92% of cell clone formation and greatly contributed to cytoplasmic DNA exposure. Subsequently, the activation of the STING pathway was observed, leading to the secretion of pro-inflammatory immune factors and maturation of dendritic cells (DCs).

Conclusion

Our study demonstrates that Dy/Mn-P NPs can potentiate tumor radiotherapy by improving the tumor microenvironment and increasing endogenous ROS levels within the tumor. Furthermore, Dy/Mn-P can amplify the activation of the STING pathway during radiotherapy, thereby triggering an anti-tumor immune response. This novel approach has the potential to expand the application of radiotherapy in tumor treatment.

Nanozymes and carbon-dots based nanoplatforms for cancer imaging, diagnosis and therapeutics: Current trends and challenges

Cancer patients face a significant clinical and socio-economic burden due to increased incidence, mortality, and poor survival. Factors like late diagnosis, recurrence, drug resistance, severe side effects, and poor bioavailability limit the scope of current therapies. There is a need for novel, cost-effective, and safe diagnostic methods, therapeutics to overcome recurrence and drug resistance, and drug delivery vehicles with enhanced bioavailability and less off-site toxicity. Advanced nanomaterial-based research is aiding cancer biologists by providing solutions for issues like hypoxia, tumor microenvironment, low stability, poor penetration, target non-specificity, and rapid drug clearance. Currently, nanozymes and carbon-dots are attractive due to their low cost, high catalytic activity, biocompatibility, and lower toxicity. Nanozymes and carbon-dots are increasingly used in imaging, biosensing, diagnosis, and targeted cancer therapy. Integrating these materials with advanced diagnostic tools like CT scans and MRIs can aid in clinical decision-making and enhance the effectiveness of chemotherapy, photothermal, photodynamic, and sonodynamic therapies, with minimal invasion and reduced collateral effects.

Drug-Primed Self-Assembly of Platinum-Single-Atom Nanozyme to Regulate Cellular Redox Homeostasis Against Cancer

Single-atom nanozymes (SAzymes) with high catalytic activity exhibit the potential to disequilibrate the reactive oxygen metabolic balance in the tumor microenvironment (TME), which contains several endogenous reductive substances such as glutathione (GSH). Herein, a novel nano-assembly (CDs@Pt SAs/NCs@DOX) is first constructed using drug-primed platinum (Pt) single-atom or nanocluster nanozymes with a Pt loading of 34.8%, which exhibits prominent dual enzymatic activities to mimic peroxidase (POD) and glutathione oxidase (GSHOx). The unique GSHOx-like activity can efficiently scavenge GSH with a relatively low Km (1.04 mm) and high Vmax (7.46 × 10-6  m s-1 ), thus avoiding single oxygen (1 O2 ) depletion. CDs@Pt SAs/NCs@DOX simultaneously demonstrates low-temperature photothermal therapy and TME- or laser-controlled disassembly and drug release, which can effectively regulate cellular redox homeostasis and achieve high tumor growth inhibition. These outcomes may provide promising strategies for the preparation of Pt SAzymes with multiple activities and variable-sized nano-assemblies, allowing for broader applications of SAzymes and nano-assemblies in the biomedical field.

Copper-Single-Atom Coordinated Nanotherapeutics for Enhanced Sonothermal-Parallel Catalytic Synergistic Cancer Therapy

Phototherapy and sonotherapy are recognized by scientific medicine as effective strategies for treating certain cancers. However, these strategies have limitations such as an inability to penetrate deeper tissues and overcome the antioxidant tumor microenvironment. In this study, a novel "BH" interfacial-confined coordination strategy to synthesize hyaluronic acid-functionalized single copper atoms dispersed over boron imidazolate framework-derived nanocubes (HA-NC_Cu) to achieve sonothermal-catalytic synergistic therapy is reported. Notably, HA-NC_Cu demonstrates exceptional sonothermal conversion performance under low-intensity ultrasound irradiation, attained through intermolecular lattice vibrations. In addition, it shows promise as an efficient biocatalyst, able to generate high-toxicity hydroxyl radicals in response to tumor-endogenous hydrogen peroxide and glutathione. Density functional theory calculations reveal that the superior parallel catalytic performance of HA-NC_Cu originates from the CuN4 C/B active sites. Both in vitro and in vivo evaluations consistently demonstrate that the sonothermal-catalytic synergistic strategy significantly improves tumor inhibition rate (86.9%) and long-term survival rate (100%). In combination with low-intensity ultrasound irradiation, HA-NC_Cu triggers a dual death pathway of apoptosis and ferroptosis in MDA-MB-231 breast cancer cells, comprehensively limiting primary triple-negative breast cancer. This study highlights the applications of single-atom-coordinated nanotherapeutics in sonothermal-catalytic synergistic therapy, which may create new opportunities in biomedical research.

Recent advances in the synthesis and applications of single-atom nanozymes in food safety monitoring

Nanozymes are synthetic compounds with enzyme-like tunable catalytic properties. The success of nanozymes for catalytic applications can be attributed to their small dimensions, cost-effective synthesis, appreciable stability, and scalability to molecular dimensions. The emergence of single atom nanozymes (SANzymes) has opened up new possibilities in bioanalytical applications. In this regard, this review outlines enzyme-mimicking features of SANzymes for food safety applications in relation to the key variables controlling their catalytic performance. The discussion is extended further to cover the applications of SANzymes for the monitoring of various compounds/biomaterials of significance with respect to food safety (e.g., pesticides, veterinary drug residues, foodborne pathogenic bacteria, mycotoxins/bacterial endotoxin, antioxidant residues, hydrogen peroxide residues, and heavy metal ions). Furthermore, the performance of SANzymes is evaluated in terms of various performance metrics such as limit of detection (LOD), linear dynamic range, and figure of merit (FoM). The challenges and future road map for the applications of SANzymes are also addressed along with their upscaling in the area of food safety.

Silymarin suppresses proliferation of human hepatocellular carcinoma cells under hypoxia through downregulation of the HIF-1α/VEGF pathway

BACKGROUND

Hypoxia is a significant feature of many solid tumors and can activate hypoxia-inducible factor 1α (HIF-1α)/vascular epidermal growth factor (VEGF) signaling pathway, which is closely related to the occurrence and development of primary liver cancer (PLC). Silymarin (SM) had been used as a traditional liver protective drug for decades. Recent studies have found that SM has chemopreventive and chemosensitizing effects on multiple cancers. In this study, we investigated the effects of SM on HIF-1α/VEGF signaling in human hepatocellular carcinoma cells under hypoxia conditions.

METHODS

HepG2 and Hep3B cells were divided into different experimental groups according to different culture conditions (aerobic or anaerobic) and the concentration of SM in the culture medium. The cellular proliferation, migration, invasion, colony formation, and apoptosis were observed by using methyl thiazolyl tetrazolium (MTT) assay, cell migration assay, in vitro invasion assay, soft agar colony formation assay, and Annexin V apoptosis assay, respectively. The cellular expressions of HIF-1α and VEGF were determined by real-time reverse transcription-polymerase chain reaction (RT-PCR) and western blot (WB) analyses.

RESULTS

SM reduced cellular proliferation, migration, invasion, and colony formation, but induced apoptosis in HepG2 and Hep3B cells under hypoxia conditions. The half inhibitory concentrations (IC50) of SM on HepG2 and Hep3B cells were 58.46 and 75.13 umol/L, respectively. SM also suppressed cellular expressions of HIF-1α and VEGF in HepG2 and Hep3B cells under hypoxia conditions at the mRNA and protein levels. All these effects of SM were dose dependent.

CONCLUSIONS

The inhibitory effect of SM on HepG2 and Hep3B cells under hypoxia is partially via downregulating HIF-1α/VEGF signaling, which may serve as a potential drug therapy target for liver cancer based on SM.

Self-cascade catalytic single-atom nanozyme for enhanced breast cancer low-dose radiotherapy

Radiotherapy (RT) efficacy can be promoted with the help of nanoenzyme that can "re-programing" the tumour's micro-environment by changing the expression level of special bio-molecules. However, problems such as low reaction efficiency, limited endogenous H₂O₂, and/or unsatisfactory results of a single catalysis mode in treatment limit the application in the RT field. Herein, a novel Au nanoparticles (AuNPs) decorated iron SAE (FeSAE@Au) was formulated for self-cascade catalytic RT. In this dual-nanozyme system, embedded AuNPs can sever as GOx and endow FeSAE@Au with self-H₂O₂ supplying ability, which can elevate the H₂O₂ level in tumors by catalyzing cellular glucose in situ, further improving the catalytic performance of FeSAE with peroxidase-like activity. The self-cascade catalytic reaction can significantly increase cellular hydroxyl radicals (•OH) level, further promoting RT's effect. Furthermore, in vivo findings demonstrated that FeSAE can effectively limit tumor growth while causing low damage in important organs. According to our understanding, FeSAE@Au is the first description of a hybrid SAE-based nanomaterial employed in cascade catalytic RT. The research yields new and interesting insights for developing various SAE systems for anticancer therapy.

Oxygen-generating biocatalytic nanomaterials for tumor hypoxia relief in cancer radiotherapy

Radiotherapy (RT), the most commonly used treatment method in clinics, shows unique advantages such as strong penetration, high energy intensity, and low systemic side effects. However, in vivo tumor hypoxia seriously hinders the therapeutic effect of RT. Hypoxia is a common characteristic of locally advanced solid tumor microenvironments, which leads to the proliferation, invasion and metastasis of tumor cells. In addition, oxygen consumption during RT will further aggravate tumor hypoxia, causing a variety of adverse side effects. In recent years, various biocatalytic nanomaterials (BCNs) have been explored to regulate and reverse tumor hypoxia microenvironments during RT. In this review, the most recent efforts toward developing oxygen-generating BCNs in relieving tumor hypoxia in RT are focused upon. The classification, engineering nanocatalytical activity of oxygen-generating BCNs and combined therapy based on these BCNs are systematically introduced and discussed. The challenges and prospects of these oxygen-generating BCNs in RT applications are also summarized.

Nanotechnological strategies to increase the oxygen content of the tumor

Hypoxia is a negative prognostic indicator of solid tumors, which not only changes the survival state of tumors and increases their invasiveness but also remarkably reduces the sensitivity of tumors to treatments such as radiotherapy, chemotherapy and photodynamic therapy. Thus, developing therapeutic strategies to alleviate tumor hypoxia has recently been considered an extremely valuable target in oncology. In this review, nanotechnological strategies to elevate oxygen levels in tumor therapy in recent years are summarized, including (I) improving the hypoxic tumor microenvironment, (II) oxygen delivery to hypoxic tumors, and (III) oxygen generation in hypoxic tumors. Finally, the challenges and prospects of these nanotechnological strategies for alleviating tumor hypoxia are presented.

Reactive oxygen species-upregulating nanomedicines towards enhanced cancer therapy

Reactive oxygen species (ROS) play a crucial role in physiological and pathological processes, emerging as a therapeutic target in cancer. Owing to the high concentration of ROS in solid tumor tissues, ROS-based treatments, such as photodynamic therapy and chemodynamic therapy, and ROS-responsive drug delivery systems have been widely explored to powerfully and specifically suppress tumors. However, their anticancer efficacy is still hampered by the heterogeneous ROS levels, and thus comprehensively upregulating the ROS levels in tumor tissues can ensure an enhanced therapeutic effect, which can further sensitize and/or synergize with other therapies to inhibit tumor growth and metastasis. Herein, we review the recently emerging drug delivery strategies and technologies for increasing the H₂O₂, ˙OH, ¹O₂, and ˙O₂^- concentrations in cancer cells, including the efficient delivery of natural enzymes, nanozymes, small molecular biological molecules, and nanoscale Fenton-reagents and semiconductors and neutralization of intracellular antioxidant substances and localized input of mechanical and electromagnetic waves (such as ultrasound, near infrared light, microwaves, and X-rays). The applications of these ROS-upregulating nanosystems in enhancing and synergizing cancer therapies including chemotherapy, chemodynamic therapy, phototherapy, and immunotherapy are surveyed. In addition, we discuss the challenges of ROS-upregulating systems and the prospects for future studies.

Metal-Based Nanozymes with Multienzyme-Like Activities as Therapeutic Candidates: Applications, Mechanisms, and Optimization Strategy

Most nanozymes in development for medical applications only exhibit single-enzyme-like activity, and are thus limited by insufficient catalytic activity and dysfunctionality in complex pathological microenvironments. To overcome the impediments of limited substrate availabilities and concentrations, some metal-based nanozymes may mimic two or more activities of natural enzymes to catalyze cascade reactions or to catalyze multiple substrates simultaneously, thereby amplifying catalysis. Metal-based nanozymes with multienzyme-like activities (MNMs) may adapt to dissimilar catalytic conditions to exert different enzyme-like effects. These multienzyme-like activities can synergize to realize "self-provision of the substrate," in which upstream catalysts produce substrates for downstream catalytic reactions to overcome the limitation of insufficient substrates in the microenvironment. Consequently, MNMs exert more potent antitumor, antibacterial, and anti-inflammatory effects in preclinical models. This review summarizes the cellular effects and underlying mechanisms of MNMs. Their potential medical utility and optimization strategy from the perspective of clinical requirements are also discussed, with the aim to provide a theoretical reference for the design, development, and therapeutic application of their catalytic effects.

Single-atom nanozymes: From bench to bedside

Single-atom nanozymes (SANs) are the new emerging catalytic nanomaterials with enzyme-mimetic activities, which have many extraordinary merits, such as low-cost preparation, maximum atom utilization, ideal catalytic activity, and optimized selectivity. With these advantages, SANs have received extensive research attention in the fields of chemistry, energy conversion, and environmental purification. Recently, a growing number of studies have shown the great promise of SANs in biological applications. In this article, we present the most recent developments of SANs in anti-infective treatment, cancer diagnosis and therapy, biosensing, and antioxidative therapy. This text is expected to better guide the readers to understand the current state and future clinical possibilities of SANs in medical applications.

Efficacy and safety of low concentration hydrogen peroxide as nasopharyngeal lavage fluid in the treatment for nasopharyngeal carcinoma radiotherapy: a pilot cohort study

Purpose: This study aimed to evaluate and analyze the efficacy and safety of low concentration (0.15%) hydrogen peroxide as nasopharyngeal lavage fluid in the treatment for nasopharyngeal carcinoma radiotherapy. Methods: Patients with nasopharyngeal carcinoma from Jiangxi cancer hospital were randomly divided into two cohorts. The training cohort (n= 50) received low concentration (0.15%) hydrogen peroxide as nasopharyngeal lavage fluid in the treatment for nasopharyngeal carcinoma radiotherapy, and the control cohort (n= 50) received 0.02% nitrofurazone lavage fluid. The primary endpoint of the study was result of short-term efficacy. Second endpoints were assessment of the linear visual analogue scale score and the incidences rate of nasopharyngeal radiation related toxicity. Results: All patients had completed the scheduled nasopharyngeal radiotherapy except two patients in control cohort. The complete response, partial response, stable disease and disease objective response of nasopharyngeal primary tumor observed in the training cohort included 18 cases, 23 cases, 9 cases and 41 cases respectively, while in the control cohort 20 cases, 25 cases, 5 cases and 45 cases were recorded, respectively. The study showed a significant discrepancy in the incidence rate of radiation-related mucosa damage between the two. Specifically, Grade 1 and 2 included 37 cases (74.0%) in the training cohort, while in the control cohort the cases were 20 (40.0%). Grade 3 and 4 damage however reported an incidence of 26.0% and 60%, respectively, which clearly constitutes a significant statistical difference (P = 0.002). The assessment of linear visual analogue scale showed that the patients self-conscious comfortable feeling in the training cohort were significantly higher than in the control cohort (P = 0.003). Conclusions: low concentration (0.15%) hydrogen peroxide as nasopharyngeal lavage fluid in the treatment for nasopharyngeal carcinoma patients is effective and safe, and can reduce nasopharyngeal local mucosa radiation related toxicity after radiotherapy.

Multifunctional nanomedicines-enabled chemodynamic-synergized multimodal tumor therapy via Fenton and Fenton-like reactions

Chemodynamic therapy (CDT) is well-known for using the tumor microenvironment to activate the Fenton reaction or Fenton-like reaction to generate strong oxidative hydroxyl radicals for tumor-specific treatment. It is highly selective and safe, without depth limitation of tissue penetration, and shows its potential as a new green therapeutic method with great clinical application. However, the catalytic efficiency of reagents involved in the Fenton reaction is severely affected by the inherent microenvironmental limitations of tumors and the strict Fenton reaction-dependent conditions. With the increasing application of nanotechnology in the medical field, combined therapies based on different types of functional nanomaterials have opened up new avenues for the development of next-generation CDT-enhanced system. This review will comprehensively exemplify representative results of combined therapies of CDT with other antitumor therapies such as chemotherapy, phototherapy, sonodynamic therapy, radiation therapy, magnetic hyperthermia therapy, immunotherapy, starvation therapy, gas therapy, gene therapy, oncosis therapy, or a combination thereof for improving antitumor efficiency from hundreds of the latest literature, introduce strategies such as the ingenious design of nanomedicines and tumor microenvironment regulations to enhance the combination therapy, and further summarize the challenges and future perspective of CDT-based multimodal anticancer therapy.

Progress and perspectives of platinum nanozyme in cancer therapy

Malignant tumors, one of the worst-case scenarios within human health problems, are now posing an increasing threat to the well-being of the global population. At present, the treatment of malignant tumors mainly includes surgery, radiotherapy, chemotherapy, immunotherapy, etc. Radiotherapy and chemotherapy are often applied to inoperable tumors, and some other tumors after surgery as important adjuvant therapies. Nonetheless, both radiotherapy and chemotherapy have a series of side effects, such as radiation-induced lung injury, and chemotherapy-induced bone marrow suppression. In addition, the positioning accuracy of radiotherapy and chemotherapy is not assured and satisfactory, and the possibility of tumor cells not being sensitive to radiation and chemotherapy drugs is also problematic. Nanozymes are nanomaterials that display natural enzyme activities, and their applications to tumor therapy have made great progress recently. The most studied one, platinum nanozyme, has been shown to possess a significant correlation with radiotherapy sensitization of tumors as well as photodynamic therapy. However, there are still several issues that limited the usage of platinum-based nanozymes in vivo. In this review, we briefly summarize the representative studies regarding platinum nanozymes, and especially emphasize on the current challenges and the directions of future development for platinum nanozymes therapy.